Xu Huijie, Guo Junli, Zhao Junjian, Gao Zhida, Song Yan-Yan
College of Sciences, Northeastern University, Shenyang 110004, China.
Anal Chem. 2023 Mar 28;95(12):5436-5442. doi: 10.1021/acs.analchem.3c00280. Epub 2023 Mar 15.
Enantioselective identification of chiral molecules is of paramount importance in medical science, biochemistry, and pharmaceutics owing to the configuration-dependent activities of enantiomers. However, the identical physicochemical properties of enantiomers remain challenging in chiral sensing. In this study, inspired by the peroxidase-mimicking activity of Fe(III)-based nanomaterials, an enantioselective artificial architecture is constructed on TiO nanochannels. Homochiral Ti-based metal-organic frameworks (MOFs) use a 2,2'-bipyridine-5,5'-dicarboxylic acid ligand as the artificial enzyme skeleton, Fe(III) as peroxidase-mimicking centers, and l-tartaric acid (TA) as a chiral recognition selector. Using l-/d-cystine as model enantiomers, the chiral moieties of l-TA on Ti-MOFs allow stereoselective recognition of guest molecules through hydrogen bonds formed between chiral cystine and the host. In a tris(2-carboxyethyl)phosphine hydrochloride-containing environment, the disulfide bonds in cystine molecules are further cleaved, and the HS-tails react with Fe(III) active sites, causing the loss of peroxidase-like performance of nanochannels. Benefitting from the nanochannel architecture's current-potential (-) properties, the selective recognition of cystine enantiomers is directly monitored through the peroxidase-like activity change-induced ionic current signatures. This study provides a new and universal strategy for distinguishing disulfide- and thiol-containing chiral molecules.
由于对映体的活性依赖于构型，手性分子的对映选择性识别在医学、生物化学和制药领域至关重要。然而，对映体相同的物理化学性质在手性传感中仍然具有挑战性。在本研究中，受铁（III）基纳米材料的过氧化物酶模拟活性启发，在TiO纳米通道上构建了一种对映选择性人工结构。同手性钛基金属有机框架（MOF）使用2,2'-联吡啶-5,5'-二羧酸配体作为人工酶骨架，铁（III）作为过氧化物酶模拟中心，L-酒石酸（TA）作为手性识别选择剂。以L-/D-胱氨酸为模型对映体，Ti-MOFs上L-TA的手性部分通过手性胱氨酸与主体之间形成的氢键实现客体分子的立体选择性识别。在含有盐酸三（2-羧乙基）膦的环境中，胱氨酸分子中的二硫键进一步断裂，HS尾与铁（III）活性位点反应，导致纳米通道类似过氧化物酶的性能丧失。受益于纳米通道结构的电流-电位（-）特性，通过过氧化物酶样活性变化诱导的离子电流信号直接监测胱氨酸对映体的选择性识别。本研究为区分含二硫键和硫醇的手性分子提供了一种新的通用策略。
